Scrapy feed output contains the expected output several times instead of just once

I've written a spider of which the sole purpose is to extract one number from http://www.funda.nl/koop/amsterdam/, namely, the maximum number of pages from the pager at the bottom (e.g., the number 255 in the example below).

I managed to do this using the LinkExtractor based on the regular expression that URLs of these pages match. The spider is shown below: